To make the
aioli, mix the mayonnaise, garlic and mustard in small bowl and set
aside. Mix the chopped chili, paprika, coriander, garlic, lime juice and
olive oil in a bowl. Season to taste with salt and freshly ground black
pepper. Add the prepared prawns and mix well. Cover and leave to
marinate in a cool place for 30 minutes.

Thread the
prawns on to skewers and grill or barbecue, basting and turning the
skewers frequently, for 6-8 minutes, or until the prawns are pink. Serve
with the aioli, garnished with whole chilies.

Piri-piri is
a Portuguese hot pepper sauce. The name means "small chili".